Black_Star,
примерно так должно быть...
$(function() {
//var $navigationTop = ... , $navigationSite и т.д.
function changeNav() {
var coord = $navigationTop.offset().top + $navigationTop.height();
if ($navigationSite.hasClass("navMob") && $(window).scrollTop() < coord) {
buttonNav.css({
display: "none"
});
navBar.show();
$navigationSite.toggleClass("navMob")
} else if ($(window).scrollTop() > coord) {
buttonNav.css({
display: "block"
});
navBar.hide();
$navigationSite.toggleClass("navMob")
}
}
$(window).scroll($.throttle(changeNav, 200))
});
